All Scheduled Events

November 9, 2009 Monday 12:35 PM 
Meyer 5th Fl. CCPP Lounge
Other CCPP (ccpp)

CCPP Brown Bag
Kyle Cranmer
NYU

Searching for exotic Higgs decays in the LEP data

November 11, 2009 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Ina Sarcevic
University of Arizona

Probing Particle Physics with Cosmic Neutrinos

Interaction of cosmic rays with the microwave background radiation provides ``guaranteed'' flux of cosmic neutrinos. In addition protons accelerated in the astrophysical source interact with ambient photons and protons producing the flux of neutrinos. I will discuss how these cosmic neutrinos could be used to probe particle physics. I will show that charm production gives rise to neutrino flux from astrophysical sources with jets driven by central engine, such as gamma ray bursts or supernovae with jets. The neutrino flux from semi-leptonic decays of charmed mesons is subject to much less hadronic and radiative cooling than the conventional flux from pion and kaon decays and therefore has a dominant contribution at higher energies, of relevance to future ultrahigh energy neutrino experiments. I will briefly discuss how cosmic neutrinos can be used as probes of supersymmetry and the challenges in detecting charged staus produced in neutrino interactions. I will illustrate how neutrinos can be used as signals of dark matter annihilation in the core of the Earth or the Sun, or in halos in the universe.

November 12, 2009 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Robert Austin
Princeton University

TBA

November 13, 2009 Friday 2:00 PM 
Meyer 6th Floor SCM Area
Hard Condensed Matter Seminars (hcmp)

Ian Appelbaum
Univresity of Maryland, College Park

Spin-Polarized Electron Transport and Electrostatic Gating in Silicon

Silicon, the materials basis for most semiconductor electronics devices, has been known for decades to have an extraordinarily long spin lifetime. Using unique spin-polarized hot-electron injection and detection techniques [1], we have observed unprecedented spin coherence, and extracted very long spin lifetimes of conduction electrons traveling over macroscopic distances [2], even in the millimeter range [3]. In this talk, I will discuss our recent work on lateral spin transport devices where a buried SiO2 native oxide serves as a gate dielectric to electrostatically control the proximity of spin-polarized conduction electrons to the interface.[4] Lattice inversion symmetry breaking, and/or coupling to paramagnetic defects, drastically affects the spin lifetime, as can be seen from time-of-flight distributions extracted from spin precession measurements. Effects seen in high magnetic fields further elucidate the mechanisms relevant to electron spin relaxation at this technologically important electronic interface.

[1] Ian Appelbaum, B.Q. Huang, and D.J. Monsma, "Electronic measurement and control of spin transport in silicon," Nature 447, 295 (2007).
[2] B.Q. Huang, D.J. Monsma, and Ian Appelbaum, "Coherent spin transport through a 350- micron-thick silicon wafer," Phys. Rev. Lett. 99, 177209 (2007).
[3] Biqin Huang, Hyuk-Jae Jang, and Ian Appelbaum, "Geometric dephasing-limited Hanle effect in long-distance lateral silicon spin transport devices", Appl. Phys. Lett. 93, 162508 (2008).
[4] H.-J. Jang and Ian Appelbaum, “Spin polarized electron transport near the Si/SiO2 interface”, Phys. Rev. Lett. 103, 117202 (2009).

November 13, 2009 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

Anze Slosar
Brookhaven National Lab

Probing primordial non-Gaussianity with today's universe

Primordial non-Gaussianity has been traditionaly constrained using three-point function of the cosmic microwave background. Two years ago, however, Dalal et al have shown that non-Gaussianity of the local type induces a scale dependent bias for biased tracers of the underlying dark matter structure. This allows constraining of the primordial non-Gaussianity from measurements of large-scale structure provided by redshift surveys. I will discuss the technique, its theoretical aspects and current results from the real data. I will also show some preliminary new results: extension to the two field inflationary models and the analogue of the Dalal effect in the Lyman alpha forest.

November 17, 2009 Tuesday 3:30 PM 
Meyer 611
Other Physics Department Events (other)

Alexander Jaoshvili
New York University

Oral Defense:
Experimental and Computational Analysis of Random Tetrahedral Packings with Applications

Committee: Paul Chaikin (Thesis Advisor)
Aditi Mitra
Jun Zhang
Engelbert Schucking
Massimo Porrati

November 18, 2009 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

David Shih
IAS

TBA

November 19, 2009 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Denton Ebel
American Museum of Natural History

Physical Processes in the Early Solar System: Evidence from Space Rocks

Physical processes active in the protoplanetary disk included gravitational instabilities (spiral waves), magnetorotational instabilities, meridional transport, vertical turbulent mixing, radiative transfer. Some temporal and spatial combination of such processes drove stellar accretion and planet formation in our (and other) solar system. Constraints on physical-chemical models are provided by the phenomenology of chondritic meteorites, interplanetary dust particles, and cometary materials (rocks), coupled with observations of young stellar disks (light). This evidence, recent results, current conundrums, and the status of 3D magnetohydrodynamic models of protoplanetary disks will be discussed.

November 20, 2009 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

Daniel Kasen
UC Santa Cruz

The Physics of Type Ia Supernovae as Cosmological Probes

Type Ia supernovae are a key element for precision cosmology missions, but the degree to which they constrain dark energy depends on how well we can calibrate them as reliable standardized candles. It is therefore important to develop a firm theoretical understanding of the physics of supernova light curves. I will explain, using both simple physical arguments and detailed numerical simulations, the origins of intrinsic luminosity variations in Type Ia supernovae and the empirical relations used to calibrate them (e.g., the Phillips relation). These theoretical studies provide a means for anticipating the potential systematic errors facing cosmology experiments, and suggest ways of obtaining more precise measurements in the future.

November 24, 2009 Tuesday 3:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

Aleks Diamond-Stanic
University of Arizona

Isotropic Luminosity Indicators in a Complete AGN Sample

December 2, 2009 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Shlomo Razamat
SUNY, Stony Brook

TBA

December 2, 2009 Wednesday 4:00 PM 
Meyer 6th Floor Conference Room
Soft Condensed Matter Seminars (csmr)

Hartmut Loewen
Heinrich-Heine-Universitat at Dusseldorf

Particle-resolved Instabilities in Colloidal Dispersions

Dispersions of colloidal particles are excellent model systems of classical statistical mechanics in order to understand the principles of self-organization processes. Using an external field (e.g. electric or magnetic field) the effective interaction between the colloidal particles can be tailored and the system can be brought into non-equilibrium in a controlled way. In this talk, we shall discuss lane and band formation in oppositely driven colloidal mixtures, both in DC and AC driving fields. The experimental realization in colloids and dusty plasmas is highlighted.

December 3, 2009 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

James Carpenter

TBA

December 4, 2009 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

David Law
UCLA

Tidal Disruption in a Triaxial Milky Way Dark Matter Halo: A Revised Model for the Sgr dSph Galaxy

Observations of the lengthy stellar streams produced by the tidal destruction of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) can provide strong constraints on the distribution of mass within the Milky Way. However, previous work has yielded conflicting results: while the angular precession of the streams has been thought to indicate an oblate shape for the Galactic halo, the radial velocities of stars in these streams are only reproduced in prolate halo models. I demonstrate that both observational characteristics are naturally reproduced by orbits within a triaxial Milky Way dark matter halo similar to that expected from current CDM theory. I conclude by summarizing the properties of the revised Milky Way --- Sgr system and discuss the possibility of using the Sgr stream to constrain the dark sector equivalence principle.

December 9, 2009 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Erick Weinberg
Columbia University

TBA

December 10, 2009 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Sal Torquato
Princeton University

TBA

December 11, 2009 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

Jennifer Siegal-Gaskins
Ohio State

Using anisotropy to identify a dark matter signal in diffuse gamma-ray emission with Fermi

Dark matter annihilation in Galactic substructure will produce diffuse gamma-ray emission of remarkably constant intensity across the sky, making it difficult to disentangle this Galactic dark matter signal from the extragalactic gamma-ray background. Recent studies have considered the angular power spectrum of the diffuse emission from various extragalactic source classes and from Galactic dark matter. I'll discuss these results and show how the energy dependence of anisotropies in the total measured diffuse emission could be used to confidently identify a signal from dark matter in Fermi data. Finally, I'll present new results demonstrating that anisotropy analysis could significantly extend the sensitivity of current indirect dark matter searches.

December 15, 2009 Tuesday 2:00 PM 
Meyer 6th Floor SCM Area
Other Physics Department Events (other)

Physics Department Holiday Reception

RSVP to Lorelei DeMesa at 212-998-7711 or lorelei.demesa@nyu.edu if you will be attending.

Light refreshments will be served.

December 16, 2009 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Christopher Herzog
Princeton University

TBA

January 22, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

January 27, 2010 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Gavin Salam

TBA

January 29, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

Vincent Desjacques
Institute for Theoretical Physics, Zurich

TBA

February 4, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Matias Zaldarriaga
IAS

TBA

February 5, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

February 12, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

February 19, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

February 24, 2010 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Alexander Turbiner
UNAM, Mexico

TBA

February 25, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Jerry Gollub
Haverford College

TBA

February 26, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

March 4, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Adam Burrows
Princeton University

TBA

March 5, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

March 11, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Janet Conrad
MIT

TBA

March 12, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

March 26, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

April 1, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Jennifer Lewis
University of Illinois at Urbana-Champaign

TBA

April 2, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

April 7, 2010 Wednesday 2:00 PM 
Meyer 5th Fl. CCPP Lounge
High Energy Physics Seminars (hep)

Samson Shatashvili
Trinity College Dublin

TBA

April 8, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Meg Urry
Yale University

TBA

April 9, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

April 16, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

April 22, 2010 Thursday 4:00 PM 
Meyer 122
Physics Colloquia (colloquia)

Alex Filippenko
UC Berkeley

TBA

April 23, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD

April 30, 2010 Friday 2:30 PM 
Meyer 5th Fl. CCPP Lounge
Astrophysics and Relativity Seminars (astro)

TBD TBD
TBD